What Animal Digs Foundations? Signs to Watch

A fresh hole beside a foundation is easy to dismiss as ordinary yard damage. But when homeowners ask, “what animal digs foundations,” they are usually seeing the start of a problem that can grow quickly: loose soil against the house, a tunnel under a porch, damaged insulation, or water moving where it should not.

In Massachusetts, groundhogs are the most common serious foundation diggers. Skunks, chipmunks, and occasionally other wildlife can also tunnel along a home, garage, shed, deck, or retaining wall. Identifying the animal matters because the right response is not simply filling a hole. An occupied den must be handled humanely, then the vulnerable area needs to be repaired and secured so the same animal, or the next one, does not return.

What animal digs foundations most often?

Groundhogs, also called woodchucks, are built for excavation. They create deep, multi-entrance burrows for shelter, winter hibernation, and raising young. A groundhog may choose a foundation because the soil has already been disturbed during construction, the wall offers a stable edge for the burrow, and nearby landscaping provides cover and food.

A groundhog entrance is often wide enough to fit a grapefruit or larger, typically 8 to 12 inches across. You may see a noticeable pile of freshly excavated soil near the opening, though not every entrance has one. Holes commonly appear along the foundation, beneath a deck or porch, at the base of a shed, or beside a retaining wall.

Skunks are another frequent concern. Their dens are generally smaller than groundhog burrows, often about 3 to 5 inches wide, and may have less dirt piled outside. Skunks prefer protected spaces under stairs, porches, decks, and additions. If the smell is unmistakable, or you notice shallow searching holes across the lawn at night, a skunk is a strong possibility.

Chipmunks make much smaller openings, usually around 2 inches wide. Their burrows can still be a concern when several tunnels develop along a walkway, patio, steps, or foundation edge. A single chipmunk hole is unlikely to undermine a sound foundation, but repeated activity can wash soil out from under hardscape and create settling problems over time.

Raccoons do not usually excavate large, true burrows like groundhogs. Still, they may pull apart soil or enlarge an existing opening to gain access under a deck, addition, or crawlspace. They are more often associated with attic, chimney, and roof entry issues. Foxes may use or enlarge old dens, particularly near wooded or open areas, while muskrats create serious burrowing concerns near ponds, streams, and waterfront structures.

Signs an animal is digging near your foundation

The size of the hole offers a clue, but it is not enough for a certain identification. Rain, soil type, and repeated use can change the shape of an entrance. A professional inspection looks at the full pattern around the property.

Fresh, loose dirt and clipped vegetation suggest an active burrow. Flattened grass, tracks, scat, gnawed plants, and paths leading to the hole can reveal which animal is visiting. Groundhogs are often seen during daylight hours feeding near gardens or brushy edges. Skunks are mostly active after dark and may leave cone-shaped holes where they have searched for grubs.

Listen, too. Scratching, rustling, or low movement under a porch can mean an animal has moved beyond the yard and into a protected void. Under decks and additions, a den may be hidden from view while the entrance remains at the foundation line.

Do not assume a quiet hole is empty. Many animals use more than one entrance, and mothers may be nursing young inside during spring and early summer. Blocking an active opening can trap animals beneath the structure, creating odor, damage, and a much more difficult removal.

Why foundation burrows deserve prompt attention

Wildlife rarely damages a concrete foundation by chewing through it. The greater risk is what happens to the soil around and beneath it. Burrowing removes support from areas that should remain compact. Water can then enter the tunnels, carry soil away, and worsen erosion around footings, steps, patios, and retaining walls.

A burrow can also create a direct path beneath a deck, crawlspace, or addition. Once an animal has a sheltered place to rest, nest, or raise young, the problem often becomes recurring. Other wildlife may use an abandoned tunnel later, especially when the opening has been left unsealed.

There are household safety concerns as well. Skunks, raccoons, and other wild animals can carry parasites and diseases. Droppings and nesting material under a structure should be handled carefully, not swept up bare-handed. Pets are also at risk when they investigate a den, especially if a skunk is inside or a mother is protecting young.

The trade-off is simple: acting too aggressively can separate a mother from her young, while waiting too long can allow erosion and access damage to spread. The safest answer is a plan that considers the species, season, location of the burrow, and condition of the structure.

A humane five-step response to animals at foundations

At Harvey’s Animal Evictions, the goal is to resolve the immediate wildlife problem while protecting the property from the next one. That process begins with evidence, not guesswork.

1. Consultation and site history. The first step is understanding when the hole appeared, whether the animal has been seen, where pets spend time, and whether there have been past problems under the same structure. Seasonal activity matters, particularly when young may be present.

2. Detailed inspection. A wildlife professional examines hole size, tracks, scat, travel routes, landscaping, deck skirting, vents, and other possible entry points. The inspection also checks for soft soil, gaps, loose lattice, damaged screening, and signs that a burrow extends under a structure.

3. Humane removal or exclusion. The method depends on the animal and the den. A one-way exclusion device may allow an animal to leave without returning, but it should only be used when it is appropriate and no dependent young will be trapped inside. In other cases, humane capture and removal may be necessary.

4. Repair and prevention. Once the space is confirmed empty, the opening can be closed correctly. This may include burying a durable barrier around a deck or shed, reinforcing vulnerable edges, repairing damaged skirting, and restoring soil so water drains away from the foundation. Simply tossing dirt into a tunnel is rarely a lasting fix.

5. Follow-up guidance. Homeowners receive practical advice for reducing future attraction, such as managing fallen fruit, securing trash, trimming dense cover near structures, and correcting drainage issues. The right prevention plan depends on the species and layout of the property.

What not to do with an active burrow

Avoid pouring chemicals, fuel, water, or concrete into a suspected den. These methods are inhumane, can contaminate soil, and may force an animal into another part of the property. They can also trap young below ground.

Do not place poison near a foundation burrow. Besides the obvious risk to children, pets, and non-target wildlife, poisoned animals may die inside an inaccessible space. The resulting odor and insect activity can create a second problem inside the home.

It is also wise to keep children and pets away from the opening until it is assessed. A calm-looking hole can be occupied, and a startled animal may defend itself when cornered.

Protecting the space after removal

Long-term prevention starts with making the area less inviting. Keep mulch, firewood, brush, and dense ground cover from creating hidden travel lanes directly beside the house. Repair gaps beneath porches and decks with materials designed to resist digging, while preserving needed ventilation and drainage.

Pay attention to water. Downspouts that discharge beside the foundation, poor grading, and leaking outdoor spigots can soften soil and make burrowing easier. Correcting these conditions protects both the building and the repaired wildlife barrier.

A hole near your foundation does not automatically mean structural failure, but it is a warning worth taking seriously. A careful inspection and humane eviction can protect the animal, your property, and the quiet comfort of home before a small opening becomes an established den.